.300 Norma Magnum

The .300 Norma Magnum, also known as .300 NM or "300 Norma" for short, is a centerfire magnum rifle cartridge developed by Swedish ammunition manufacturer Norma Precision. The .300 Norma Magnum uses a .338 Norma Magnum case necked down to the .30 caliber,[1] named to differentiate it from the older .308 Norma Magnum designed in 1960, and has begun to gain popularity in the long-range shooting community. According to the official C.I.P. (English: Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) rulings the .300 Norma Magnum can handle up to 440.00 MPa (63,817 psi) Pmax piezo pressure.

The United States Special Operations Command (USSOCOM) chose the new MK22 Advanced Sniper Rifle which will be chambered in .300 Norma Magnum (designated M1163) as well as 7.62x51mm and .338 Norma Magnum.